Polymers of cationic monomer, such as dimethyldiallyl ammonium chloride, have been prepared via solution polymerization techniques (U.S. Pat. No. 3,288,770). The intrinsic viscosity of the polymeric products of the process is indicative of the molecular weight of the polymer. Values of 0.5 to 2.0 dl/g in 0.1 N potassium chloride were indicated. The intrinsic viscosities would be considerably lower in 1.0 M NaCl.
U.S. Pat. No. 3,284,393 discloses that water-in-oil emulsion polymerization techniques are useful for polymerization of water-soluble monomers.
U.S. Pat. No. 3,968,037 discloses that the water-in-oil emulsion polymerization of cationic monomer containing crosslinking agents results in water-soluble polymer useful as flocculants and for the treatment of activated sewage sludge.
East German Pat. No. 141,028 discloses the control of pH to allow for the low temperature solution polymerization of diallyldialkyl ammonium chloride.
Jaeger, W., et al, "Synthesis and Polycation-Polyanion-Interaction of Poly(Dimethyl Diallyl Ammonium Chloride)", Polymeric Amines and Ammonium Salts, edited by E. J. Goethals, Pergamon Press, New York, 1980, discloses the effect of salts on the rate of solution polymerization of dimethyldiallyl ammonium chloride.
U.S. Pat. No. 3,920,599 discloses that homopolymers of diallyldimethyl ammonium chloride as well as copolymers with acrylamide can be prepared in water-in-oil emulsion polymerization, requiring considerable time at high temperatures to form stable polymeric latices. The intrinsic viscosities of these polymers is in the area of 0.7 dl/g.
It was surprisingly found that the pH range and salt content parameters of the instant invention resulted in a different polymer, prepared via the water-in-oil emulsion polymerization technique than produced at a lower pH and/or in the absence of salt.
It was further found that the products of the process of the instant invention were stable for at least three weeks and were capable of being inverted rapidly in water to form a solution.
Finally, the polymer concentration, with respect to the emulsion, varies between 20 to 75 percent by weight, containing a polymer with an intrinsic viscosity above 1.5 dl/g, when measured in 1.0 M NaCl.